Signalling drift indicator with knob extension



Oct. 7, 1969 R. L. ALDER 3,470,620

SIGNALLING DRIFT INDICATOR WITH KNOB EXTENSION Filed May 5, 1967 United States Patent 3,470,620 SIGNALLING DRIFT INDICATOR WITH KNOB EXTENSION Robert L. Alder, Pasadena, Calif., assignor to Byron Jackson, Inc., Long Beach, Calif., a corporation of Delaware Filed May 5, 1967, Ser. No. 636,462 Int. Cl. E21b 47/02 US. Cl. 33205 3 Claims ABSTRACT OF THE DISCLOSURE A signalling drift indicator having a knob provided with an upward extension consisting of a ring portion of a diameter sufficient to cooperate with a set of pulse rings to produce pressure pulses and a cylindrical portion of smaller diameter for restricting the bypass flow area past the knob when the knob is between pulse rings.

The present invention relates to signalling drift indicators for use in the drilling of boreholes or wells into the earth and more particularly to improvements in the signal producing means whereby to enhance the operation of the drift indicators, especially when air or other gas is employed as the drilling fluid which removes the cuttings as the drilling progresses.

Signalling drift indicators of the general type here involved are disclosed in United States Patents Nos. 2,435,- 934, issued Sept. 10, 1948, to F. M. Varney et al., and 2,762,132, issued Sept. 11, 1956, to J. A. Varney, as well as in United States Patent No. 3,176,407, issued Apr. 6, 1965, to R. L. Alder et al. In these prior inventions pressure pulses or signals are produced in the stream of drilling fluid adjacent the drill bit and are detectable at the surface of the earth as an indication of the angle of the lower end of the drill string from vertical, such signals being generated in a number which is either directly or inversely related to the angularity of the drill string adjacent the bit.

Such device are of substantial benefit to the driller in determining whether he is maintaining desired or proper control of the weight applied to the bit with resultant control of the progression of the hole relative to a selected angle or relative to vertical, as well as being of substantial benefit to the driller in determining relative bit efiiciency, i.e., whether the bit should be changed to enable increased penetration rate at a given depth in the light of the time required to make a round trip of the drill pipe to change bits, all as is now well known in the art.

Heretofore, in the use of devices of the general type described above, it has been the practice to cause operation of the signal producing means in response to the cessation and resumption of the circulation of drilling fluid. In such devices, cessation of drilling fluid circulation allows the upward travel of a flow pressure responsive head or knob through a series of restrictions, and resumption of drilling fluid circulation causes the downward travel of the knob through a number of the restrictions related to the angle of the drill string, or more precisely the drill collar sub, in which the knob is disposed. Means are included in such devices which are operative in response to gravity to limit upward travel of the knob in a particular relation, direct or inverse, to the angle of the sub. Such upward travel of the knob is caused by spring means in the instrument housing acting on a shaft which supports the knob. The upward bias of the spring means must be overcome by the action of the drilling fluid on the knob. However, between the restrictions, or so called pulse rings, which cooperate with the knob to produce pressure pulses in the stream of drilling fluid, are spaces 3,470,620 Patented Oct. 7, 1969 "ice which provide substantial bypass flow area around the knob. Particularly when air is employed as the drilling fluid such bypass flow area around the knob may cause such a reduction in the force acting on the knob to move it downwardly against the spring means that the knob may not properly move downwardly.

Accordingly, an object of the present invention is to provide a signalling drift indicator of the above generally referred to class, wherein an improved knob construction is employed to enhance the downward movement of the knob.

More specifically, an object is to provide a knob construction whereby the bypass flow area past the knob when it is between restrictions is limited so that suflicient fluid force is applied to the knob to assure its continued downward movement. In this connection, I provide a knob which includes an upward extension which when the knob is between restrictions or pulse rings reduces the available flow area between the knob and at least the superjacent pulse ring so that the fluid will impose on the knob suflicient pressure to force the knob downwardly through the subjacent pulse ring.

Another object is to provide a knob construction in accordance with the foregoing objectives which is adaptable to use under various conditions of drilling fluid flow and pulse ring sizes by means of changing the size or form of the upward extension of the knob. Moreover, with such a knob construction, the instrument is rendered more useful for air drilling operations without requiring modification or change of the pulse ring structure which may thus be used either with liquid or air as the drilling fluid.

Other objects and advantages of the invention will be hereinafter described or will become apparent to those skilled in the art and the novel features of the invention will be defined in the appended claims.

In brief, the present invention resides in a signalling apparatus adapted to be installed in a well drilling string for producing pressure pulses in a stream of well drilling fluid indicative of the angular disposition of the drilling string, which apparatus includes: a tubular body adapted to be installed in the drilling string, signalling means in the body including an instrument for producing the pressure pulses following interruption of the flow of drilling fluid through the body and responsive to the resumption of flow of drilling fluid through the body, the signalling means also including axially spaced pulse rings and intervening spaces in the body and a knob movable in one direction through the pulse rings upon interruption of the flow of drilling fluid and movable in the other direction through the pulse rings by the action of the drilling fluid upon resumption of the flow of the drilling fluid, the improvement wherein the knob includes a portion of major size cooperative with the pulse rings for producing pressure pulses as the knob moves therethrough in the other direction, and a portion of minor size extending from the major portion and cooperative to restrict the flow of drilling fluid through the pulse rings when the major portion of the knob is in the spaces between the pulse rings, wherein the major portion comprises a ring and the minor portion comprises a cylindrical extension of a diameter less than the ring. The minor portion of the knob may have an extension at least equal to the space between adjacent pulses rings.

In the drawing:

FIG. 1 is a view in longitudinal section, with certain of the parts shown in elevation, illustrating a signalling drift indicator made in accordance with the invention, with the knob in the full down position.

FIG. 2 is an enlarged fragmentary view in section showing the knob in an upper position and in section.

Like reference characters in the drawing and in the following description designate corresponding parts.

Referring first to FIG. 1, there is shown an instrument I made in accordance with the invention and disposed in a drill collar sub C, having a body 1, pin end 2, and a box end 3 for threaded connection in the drill string. Pin end 2 is formed on a cap 4 which issuitably removably connected to the body 1 as by a thread (not shown) whereby the instrument may be installed in the body 1. This instrument includes a pulse or signal producing section P and a shaft and pendulum section S. This latter section S includes a housing 5 at the lower end of which is a bottom support 6 in the form of a spider providing flow passages 7, this bottom support seating on a shoulder 8 at the bottom of drill collar body 1. Housing 5 of section S is connected by a spider 9, having flow passages 10, to the pulse section P.

Pulse section P includes a pulse ring fitting 12 which is a tubular member welded at 13 to, or otherwise made a part of, the spider 9. This fitting 12 fits within drill collar body 1 and has an upper flange 14 which seats on a shoulder 15. Means are provided to form a seal between the fitting 12 and drill collar body 1, and illustratively such means includes a resilient seal ring 15 carried by fitting 12 and engaged in body 1. Within the fitting 12 is a vertically spaced series of pulse rings 16 providing successive restrictions and enlarged flow areas whereby to produce pressure pulses in the stream of drilling fluid as a knob 17 of novel construction hereinafter to be described, passes downwardly therethrough in a manner hereinafter to be described.

The knob 17 is supported at the upper end of a shaft 18 which extends vertically and slidably through a seal 19 carried at the upper end of shaft and pendulum section S of the instrument I. Within the instrument housing 5, a main spring 20 acts on a flange 21 of shaft 18 to normally bias the shaft and knob upwardly and to move it upwardly when the circulation of drilling fluid is interrupted. Means are provided within the housing 5 for limiting upward movement of shaft 18 a distance related to the angle of drift of the drill collar C and the well from vertical, so that upward movement of knob 17 will be correspondingly limited.

.As seen in FIG. 1, these means comprise a pendulum 22 pivotally supported beneath shaft 18 by bail means 23 and having a head 24 providing a shoulder which is selectively engageable with one of a plurality of axially spaced annular stops 25 of progressively diminishing diameter. It will be recognized that the angular disposition of the drill collar C relative to the pendulum 22, which, being gravity responsive will depend vertically from its pivot, will determine which stop 25 will be engaged by pendulum head 24; and that, while in the structure shown the permitted upward travel of the pendulum and the shaft is inversely related to theangular disposition of the body, i.e., the greater the angle the less the travel, the assembly may include a coding system for enabling a direct relationship between angle and extent of shaft travel, as disclosed in the aforesaid United States Patent No. 3,176,407.

In either event, downward movement of the knob 17 from the position shown in FIG. 2 to the original position shown in FIG. 1 responsive to flow of drilling fluid through the pulse rings 16 will cause the production of pressure signals in the fluid stream which are detectable at the earths surface for purposes of indicating the angle of the drill collar.

In order that the pulses will be of suflicient duration as to be easily discriminated from normal pressure variations in the fluid stream, a clean body of oil in the shaft and pendulum section S is displaced through an orifice assembly including a number of orifice discs 26, which are disposed in a passage 27 in a combined disc support and pendulum seat 2 8 which is mounted in the section 5 between rings 29. A by-pass passage 30 and a downwardly closing check valve 31 are provided in the support 28 for allowing relative freedom of upward movement of instrument fluid in section S through support 28 during upward movement of shaft 18.

This clean oil or instrument fluid is retained in the body 5 of section S by means of seal ring 19 at the upper end of body 5 and by a pressure equalizing divider below the support 28. The divider in the illustrative embodiment is in the form of a diaphragm 32, but a free piston may also be employed.

The instrument as thus far described is substantially conventional, but in accordance with the present invention the fluid pulse producing or signalling means is so constructed that as the knob 17 is moving downwardly through the pulse rings a portion of the knob cooperates with at least the superjacent pulse ring to impede or restrict the flow of drilling fluid through the pulse rings, whereby to maintain adequate fluid force on the knob to cause continued downward movement of the latter.

As best seen in FIG. 2, the knob 17 comprises a thimble 17a detachably mounted upon the upper end of shaft 18 by means of a cross pin 17b, the thimble shouldering on the shaft at 17c and having an outwardly projecting abutment flange 17d at its base. Detachably disposed about the thimble 17a and seating on flange 17d is a ring 17:: which projects outwardly beyond flange 17d, the outer periphery of the ring 17e being of a diameter only slightly less than the inside diameter of the pulse rings 16 so that, upon passage of the knob ring 17e through the pulse rings 16, the flow of drilling fluid will be so restricted or impeded as to cause the production of a signal or pressure pulse in the fluid stream, as previously indicated. Detachably mounted on the thimble 17a and engaged with the knob ring 172 to hold the latter against the flange 17d is an upward extension piece or head 17) through the upper end of which extends a fastener 17g, this fastener engaging in a threaded bore in the thimble 17a to retain the knob elements in assembled relation.

This knob head 17 is of a reduced diameter as compared with knob ring 172 and is of such an axial extent as to extend upwardly into at least the pulse ring 16 above the knob ring 172 when the latter is passing through the pulse rings, that is, when the knob ring 17a is in one of the spaces 16a intervening between rings 16. Thus, the knob head 17 constitutes a knob portion of minor size, in relation to the major size of the knob ring 17e, whereby to restrict the flow of drilling fluid through the pulse rings 16 when the knob ring 17e is in the spaces 16a. Therefore, loss of drilling fluid through the otherwise comparatively large flow area between the pulse rings in spaces 16a and the knob ring 17e is prevented.

Moreover, it is notable that the present knob assembly may be made up of knob rings and knobheads of different relative major and minor proportions in relation to the particular pulse ring 16 and spaces 16a of the instrument, so that the otherwise conventional instrument useful in detecting angular deviation and producing pressure pulses indicative thereof when liquid is employed as the drilling fluid may be adapted to use when air or other gases, herein generically termed air, are employed as the drilling fluid.

It is seen from the drawings that the head of minor portion 17f is contiguous to the knob ring or major portion 17a and that the minor portion is located behind the major portion in the sense that it follows the major portion as the knob ,moves downwardly in response to resumption of the flow of drilling fluid through the instrument body 1. 1

While the specific details of the invention have been herein shown and described, changes and alterations may be resorted to without departing from the spirit of the invention.

I claim:

1. In a signalling apparatus adapted to be installed in a well drilling string for producing pressure pulses in a steam of well drilling fluid indicative of the angular disposition of the drilling string, said apparatus comprising: a tubular body adapted to be installed in the drilling string, signalling means in said body including an instrument for producing said pressure pulses following interruption of the flow of drilling fluid through said body and responsive to the resumption of flow of drilling fluid through said body, said signalling means also including axially spaced pulse rings and intervening spaces in said body and a knob movable in one direction through said pulse rings upon interruption of said flow of drilling fluid and movable in the other direction through said pulse rings by the action of the drilling fluid upon resumption of the flow of said drilling fluid, the improvement wherein said knob includes a portion of major size cooperative with said pulse rings for producing pressure pulses as said knob moves therethrough in said other direction, and .a portion of minor size extending from said major portion and co-; operative to restrict the flow of drilling fluid through the pulse rings when said major portion of said knob is in said spaces between said pulse rings, wherein said major portion comprises a ring and said minor portion comprises a cylindrical extension of a diameter less than said ring.

2. In a signalling apparatus adapted to be installed in a well drilling string for producing pressure pulses in a stream of well drilling fluid indicative of the angular disposition of the drilling string, said apparatus comprising: a tubular body adapted to be installed in the drilling string, signalling means in said body including an instrument for producing said pressure pulses following interruption of the flow of drilling fluid through said body and responsive to the resumption of flow of drilling fluid through said body, said signalling means also including axially spaced pulse rings and intervening spaces in said body and a knob movable in one direction through said pulse rings upon interruption of said flow of drilling fluid and movable in the other direction through said pulse rings by the action of the drilling fluid upon resumption of the flow of said drilling fluid, the improvement wherein said knob includes a portion of major size cooperative with said pulse rings for producing pressure pulses as said knob moves therethrough in said other direction, and a portion of minor size extending from said major portion and cooperative to restrict the flow of drilling fluid through the pulse rings when said major portion of said knob is in said spaces between said pulse rings, wherein said knob comprises a thimble, a knob supporting shaft on which said thimble is mounted, said major portion of said knob comprising a knob ring removably disposed on said thimble, and said minor portion of said knob comprising an extension piece removably connected to said thimble and engaging said knob ring to hold the latter on said thimble.

3. Signalling apparatus as defined in claim 1, wherein said minor portion is contiguous to said major portion and is located behind said major portion in the sense of said other direction of movement of said knob,

References Cited UNITED STATES PATENTS 3,176,407 4/ 1965 Alder et al. 2,762,132 9/ 1956 Varney. 2,435,934 9/1948 Varney et al.

LEONARD FORMAN, Primary Examiner F. J. DAMBRASIO, Assistant Examiner 

